Wool shrinkproofing baths containing butadiene copolymers and their utilization



ts... Aug. 24, 1948 TAININ G BUTADIENE COPOLYMEBS arm 'rnam u'rmiza'nox John B. Rust,

olair Belem New Jersey Montclair, N. 1., minor to Month Corporation, a corporation of No Drawing. Application August 28, 1945,

Serial No. 818.200

such polymerization products, and to methodsof making such products and compositions and of treating wool therewith.

Among materials that have heretofore been suggested for the treatment of wool. may be men'- .tioned methacrylate resins, butadiene copolymers, etc. Those suggestions in the art treat all of these polymeric substances as equivalent for all fibers. But investigation proves that. such suggestions are erroneous because while'any of i the synthetic resins referred to can be applied to wool for example, they are not equally eflicacious in effecting a shrink-proofing effect. And this is true even of copolymers of butadiene 1.3 derivatives.

Among the objects of the present invention is the production of copolymers particularlyvaluable in the shrinkprooilng of wool but having other utilities as well. g

Further objects include the production of baths, emulsions and compositions containing such copolymers.

Further objects include methods'of preparing such copolymersand baths, emulsions and compositions containing them.

Still further objects include methods of treating wool for shrink-proofing.

Other objects and advantages of the invention will appear from the more detailed description set forth below, it being understood that this more detailed description is given by way explanation and illustration onlyyand not by way of limitation, since various changes therein may be made by those skilled in the art without departing from the scope and spirit of the present invention.

In accordance with the present invention it has been found that copolymers of butadiene 1.3 and a 2 methyl butadiene 1.3 may be prepared and utilized to give excellent shrink'prooiing of wool. Such copolymers may be prepared at high speeds in a relatively short time to produce copolymers possessing valuable properties.

As illustrative of the 2 methyl butadienes there may be mentioned isoprene (2 methyl butadiene 1.3) and 2.3 dimethyl butadiene 1.3 ,which will be used below toexemplify the invention.

While various methods of producing the copolymers may be employed, the most desirable method is to carry out thee polymerization in an aqueous medium or emulsion'in the presence of a polymerization catalyst. The conditions of recopolymer may be directly obtained and uti- SOIaims. (Cl. zoo-29.1)

action determine the speed or reaction velocity as well as the characteristics of the products obtained; although the nature ofthe interpolymerizing constituents has an important effect on those characteristics; and in some instances the proportions of the copolymer ingredients affeet the properties insofar as shrinkprooflng of wool is concerned. The preferred process includes'the steps of heating a mixture of the constituents to be copolymerized with water in the presence of an emulsifying agent and a polymerization catalyst, particularly a peroxide catalyst, in a pressure reactor at a controlled temperature and pH, using agitation to maintain a good emulsion. In this way, emulsions containing the lized by adjustment and additions as the treating bath for treating the wool to produceshrinkproofing.

By utilizing pressures in excess of atmospheric, the time periods involved may be greatly shortened and the reactions greatly accelerated even at relatively low orders of temperature, to give very satisfactory products. As indicated above,

a satisfactory way of carrying out the reaction I should be'acourately adlusted as by neutralizapart tion and stabilized as by means of suitable buifering agents at that value best suited for the emulsifying agent employed. Depending upon acetates. borates, phosphates. and the like, vor

mixt res thereof. The pH employed depends in n the type of emulsifying agent used. Emuls lying agents should be used which are stable at the pH concentration employed. With an emulsifying agent which is most emcient unw 'der acid conditions, a pH below '7 is desirable. On

are most eificient under basic conditions, a pH above 7 should be employed.

As emulsifying agents, there may be employed a wide range of materials such as sodium lauryl sulfate, sodium alkyl naphthalene-sulfonate, higher esters of sodium sblfosuccinic acid, sodium olea-te, triethanolamine oleate, and the like. The amount of emulsifying agent may be varied depending upon the condition of agitation. Commonly there may be used about of emulsifying agent based on the water phase, but with vigorous agitation considerably less may be employed. Since soap is the cheapest emulsifying agent, and since its emulsions can be easily broken by addition of a small quantity of acid, it is the preferred emulsifier. The proportion of water to be used in the emulsion is subject to wide variation. However, avoiding unnecessarily large quantitie of water, enables smaller equipment to be employed.

Reaction temperatures of from 30 to 100 C. may be employed, but more desirably the reaction is carried out between temperatures of 30 to 60 C., particularly under the preferred conditions of operations as illustrated herein.

As indicated, the reaction is desirably carried out in the presence of a polymerization catalyst and any suitable oxygen-giving compound may thus be employed. Preferably the less expensive material such as hydrogen peroxide, ammonium persulfate, benzoyl peroxide, and the like may be utilized.

While additive agents in the emulsion are not necessary, they are often advantageous. Protective colloids may be employed such as gelatin, glue, methyl cellulose, agar agar, alginates, pectates. e g albumin, and the like.

The temperature, amount of catalyst, emulsifyingagent, efflciency of agitation, additive agents, and the like, all have an influence on the velocity of the reaction. When the reaction has proceeded as far as desired, there may be added an antioxidant such asphenyl beta naphthylamine, alkyl aromatic amine, hydroquinone monobenzyl ether, and the like. The presence of antioxidant has an important effect other than merely as an antioxidant in the usual sense, since the presence of such materials in the emulsions and baths used for shrink-proofing wool, exert an effect whereby the shrinkproofing is enhanced beyond that obtained in its absence. So that antioxidants in these cases have an unexpected and unpredictable effect.

The interpolymeriza'tion products are produced in latex-like form when the reactions are carried out in aqueous emulsion as indicated above, and such latex-like products may be utilized as such, for example, in the treatment of textiles, preferably after adjustment as indicatedbelow, 'or they may be employed'in other ways.

As formed, the emulsions contain the copolymer in a condition in which it is unsuitable as synthetic rubber or rubber-like material. If coagulated by any suitable means, the emulsions give crumbly materials which cannot be milled or sheeted as on rubber milling equipment in the way that rubber is manipulated. The copolymer is in the form where extensive cross-linking has occurred as further pointed out below.

To enhance such materials for use for shrinkproofing. they may desirably be given an oxidation treatment, preferably while in aqueous emulsion as obtained from the polymerization step, to convert them into What may bev called a pre-vulcanized condition so that upon deposition of the polymer on, in or about the fibers or textiles, the polymer is in a non-tacky condition and gives a nontacky deposit. Or the polymer in such emulsions utilized in accordance with the present invention is in a condition in which it is substantially insoluble in organic solvents such as benzene, toluene, xylene, carbon tetrachloride, chloroform, and tetr-achlorethane, but, however, may be swollen to some extent with such solvents. The vulcanization has been carried to a point where substantially no soluble polymer remains, but, a stated above, the gel-forming polymer may be swollen to some extent with the statedsolvents.

Where such prevulcanization by oxidation is employed, the emulsions are prepared by carrying out the polymerization in the presence of polymerizing agents in which emulsions the polymer or copolymer is present in such condition that if deposited on fibers a tacky deposit would be obtained, or the polymer is substantially soluble in common organic solvents at this time, or is incompletely vulcanized, and second, the emulsion or no monomer is present. The emulsion at this point may be subjected to vacuum or other treatment to remove any volatile hydrocarbons which may be present, before the step of oxidative vulcanization. The term oxidative pre-vulcanization may be used to describe the final condition of the polymer in the emulsion without any implication that an oxygen link is necessarily involved.

Such oxidative pre-vulcanization may be carried out at temperatures for example of 70-400 0., with oxygen yielding substances such as hydrogen peroxide, benzoyl peroxide, ammonium persulfate, acetyl peroxide, butyl hydroperoxide, butyl perbenzoate, etc., for a period of from 45 minutes to 1 hours. Such oxidative treatment of the emulsion is desirably carried out in the absence of the antioxidants, the latter bein added after the oxidation treatment has been carried to the point desired. This addition of antioxidant is desirable so that further oxidative change will not continue after the material has been applied to the textile.

The emulsions produced as set forth above may be used for the treatment of wool either as raw wool, yarn, knit, woven goods or mixed goods,

etc.- The wool to be treated is entered into the' bath containing the copolymer produced as set forth above. Water may be added to such emulsions to produce the desired bath content. The bath should contain the copolymer in an amount to give, under the conditions of treatment, a wool having from 1% to 25% of copolymer based on the weight of the wool. The bath is desirably conditioned by adding to it a suificiently strong electrolyte to allow the deposition of the copolymer on the wool fibers. It has been found that in such a bath no deposition of copolymer occurs under ordinary conditions. However, upon the addition of an electrolyte, exhaustion of the bath will take place with varying rapidity, depending mainly upon temperature and electrolyte concentration. Without any limitation by way of theoretical considerations. it is believed that reversal of the electrical charge on the colloidal particles of the copolymer takes place on addition of the electrolyte enhancing the aifinity of the copolymer for the fiber. trolyte added would be insuificient Ito account'on a theoretical basis for the salting out of the co- The proportion of the elecpolymer particles. Thus the effect must be one butadiene may be varied over wide limits and a pronounced shrinkproofing efiect obtained. Thus with isoprene, 2 methyl butadiene 1.3, excellent non-shrinking and non-felting effects are -obtained, within wide limits as for example with from to 80% of isoprene based on the total weight of copolymer. With 2.3 dimethyl butadiene 1.3, good results are obtained with from 10% to 80% of the latter based on the total weight of the copolymer, but the best results are obtained with from 10% to 70%.

The electrolyte content may vary over substantial limits but sufiicient electrolyte should be present to condition the bath so that the bath, although stable in the presence of the wool fibers, will deposit the polymer in the presence of the conditioning electrolyte. Thus the electrolyte content may vary from about 25% to about 500% based on the weight of the copolymer present. The following are exemplary: sodium sulphate, chloride, bromide, iodide, sulfite, bisulfate, bisuliite, nitrate, acetate and the like, or the corresponding potassium, lithium, caesium salts, etc. Salts like zinc chloride may also be used where the coagulation does not appear to be too serious since it occurs in small particulate form and the particles may be redispersed by stirring. .As such electrolyte water-soluble salts may be used, desirably such salts which do not precipitate the polymer, neutral salts, specifically salts of strong bases and strong acids, particularly inorganic salts are preferred. The term conditioning electrolyte" is used hereinafter to cover such electrolytes which produce the desired deposition of the polymer. It has been found that it is possible to deposit the emulsions of the present invention on wool at a pH of '7 or even slightly higher. However, it is preferred tooperate at a pH of 7 or below since under these conditions more rapid dispersal is effected.

The operation is desirably carried out at a temperature suificient to give exhaustion of the bath with the particular emulsion being used. This will vary with different emulsions. While lower temperatures may be used, the operation is ,desirably carried out at temperature ranges from 40 C. to the boiling point of the bath.

The polymer can be applied before or after fulling, weaving, scouring and the like operations. In some cases it can be applied in the dye bath. Mixed goods including wool-cotton. wool rayon and so forth can be treated by this method without any deleterious effect. If desired the wool may be subjected to a. pretreatment, as for example, chlorination or bromination, before being treated in accordance with the present invention.

As emulsifying agents, anionic emulsifying agents which are stable at or below pH 7 are prepolymer is obtained, considerable cross linkingv occurs in the polymer with consequent insolu-. bility in organic solvents. 'Thus a type of prevulcanizing of thepolymer has been obtained.

It is also possible to vulcanize the copolymers with mixtures of vulcanizing accelerators such as thiuram disulfide and so forth, vulcanizing agents such as sulfur, dinitrobenzene, alkyl phenol sulfide and so forth, either previously or subsequently to deposition or dyeing into the wool fibers.

The treatment of wool fibers is particularly emphasized herein, although animal fibers such as silk and protein fibers such as "Aralac" (a casein fiber) may also be treated in accordance with this invention.

After treatment in accordance with the present invention, the wool is rinsed and dried. Its properties have been altered to such a degree that it no longer has a tendency to felt during washing and consequently is non-shrinking. Although it is not intended that the invention be limited by theoretical considerations, it is thought that the copolymer particles applied as set forth in this description distribute themselves among the fibers of the wool and in some instances fill the interstices of the wool scales, thus preventing an intertwining and consequent felting of the wool. Thus the deposited copolymer would prevent intertwining of the wool fibers and also permit relatively easy slippage of the fibers one on the other.

The following examples illustrate the invention, the parts being by weight unless otherwise indicated. I

Example 1.-A- series of isoprene-butadiene polymer emulsion was prepared. 'The two monoi mers were used in the proportions indicated in The butadiene was passed over CaCl: and condensed in pressure reactors which were cooled to below --5 C. The liquid butadiene was then transferred to a Dewar flask and kept there until added to the reaction mixture. The isoprene, whichhad been distilled at 34-35 C. under normal pressure, was weighed out and poured into the pressure reactors. In all cases parts of buifer, parts of 30 hydrogen peroxide solution and 5 parts of sodium lauryl sulfate were added, while the pressure reactors were still kept in the freezing mixture. The bufier solution had been made up by dissolving 35.3 parts of disodium phosphate and 7.16 parts of trisodium phosphate.

actor with emulsion #1 showed a very slight pres-' sure, but no foaming. None of the others showed any pressure or foaming. In the caseof emulsions #1 to #8, which contained butadiene, this indicated complete polymerization, i.- e., a polymer content of 33 A;%. The polymer content of emulsion #9 was determined and was found to be 30 Example 2. The nine emulsions made according to Example 1 were applied to hand knit wool samples approximately 7" x 5" in size. An amount of emulsion containing polymer corresponding to 6% of the weight of the wool sample to be treated was weighed and added to 200 parts of water. The weights of the cool samples and the. corresponding amounts of emulsion are listed in Table II. The bath was conditioned in each case with an electrolyte consisting of 1.0 part of anhydrous sodium sulfate, and 1.0 part of '10% sulfuric acid was added. The wool sample was immersed in the cold bath, and the bath was then heated to 6070 C. After 20 minutes at this temperature a second portion of 1.0 part anhydrous sodium sulfate .was added to each bath. The

heating to 60-70 C. was continued until exhaustion occurred. In the case of emulsions #1 to #4 this took 5065 minutes at 60-70" C., for the other emulsions it took slightly longer anda slighthaze remained while emulsions'#1 to #4 cleared up completely. The wool samples were then rinsed and dried.

two monomers were used in the proportions indicated in Table III.

Table III Parts 2 i- Parts Bu- Dimetbyl- Butadieno dime i l a. a. 75 8.76 4 6. 00 7. 50 5 6. 25 6. 25 6 7.50 5.00 7 8.75 3.15 ,8 10. 00 2. 60

The butadiene was passed over CaCl: and condensed in pressure reactors cooled to below 5 C. The liquid butadiene was then transferred to a Dewar flask and kept there until added to the reaction mixture. The 2,3-dimethyl butadiene was weighed out and poured into the pressure reactors. To each reactor were added 25 parts of buffer, 1.25 parts of 30% hydrogen peroxide solution and 1.25 parts of sodium lauryl sulfate, while the pressure reactors were still kept in the freezing mixture. The buffer solution had been made up from 35.8 parts of disodium phosphate and 7.16 parts of trisodium phosphatedissolved in 980 parts of distilled water. Except for emulsion #9, which did not get any butadiene, the butadiene was now added to the reaction mixture in the pressure reactors and the reactors were closed. They were allowed to come to room temperature and were then put in an agitator with a constant temperature bath at C.

All reactors were taken out after 16 hours in the agitator. The reactors were cooled and opened. Emulsions #1 and #2 showed very slight pressureand very slight foaming on opening, while noneof the others showed any pressure or All nine samples were then washed for 6 hours in a washing machine containing 25 parts of powdered soap in 13,000 parts of water at 70 C. The samples were then rinsed and dried.

The extent of the felting and shrinkage caused by the washing is shown in Table II.

The emulsions containing butadiene were all very effective shrinkproofing agents, regardless of the percentage of butadiene present, while emulsion #9, which contained only isoprene, had some shrinkproofing properties, but was not as effective as the other emulsions.

Example 3.A series of dimethyl butadienebutadiene polymer emulsions was prepared. The

foaming. Thus complete polymerization was assumedin all cases and the polymer content was therefore 33%% in each case.

' Example 4.---The emulsions made according to Example 3 were applied to handknit wool samples approximately 7" x 5" in size. An amount of emulsion containing a-welght of polymer corresponding to 6% of the weight of the wool sample to be treated was weighed out and added to 300 parts of water. The weight of the wool samples and the corresponding amounts of emulsion are given inTable IV. The bath was .conditioned in each case with an electrolyte consisting of 1.0 part of anhydrous sodium sulfate, and 1.0 part of 10% sulfuric acid was added. The wool sample was immersed in the cold bath, then-heated to 60-70 C.- After 20 minutes at this temperature the bath had not yet cleared andanother portion of 1.0 part of anhydrous sodium sulfate was added to each bath. The bath with emulsions #5 to, #8

4 received a third'portion of 1.0 Part of anhydrous sodium sulfate 20 minutes after the second addition, the remaining baths received the same amount approximately 40 minutes after the second addition. The exhaustion time varied between 1 and 2 hours, counted from the time the baths reached a temperature of 60 C. The wool samples were rinsed and dried. Samples #5 and #6 felt slightly sticky, while .samples #7 to #9 showed a considerable stickiness. There seemed to be a definite increase in stickiness with increasing dimethyl butadiene content of the polymer. a

Table IV l i Parts 2 3- Parts Parts Parts Shrinkage and Dimethyl Buta- I Bumdlene (we Wool Emulsion FeLiug 1 i 90 14. 66 2. 62 Very slight. 2 80 i4. 30 2. 68 Do. 3 i0 70 14.40 2. 6i Do. 4 60 i5. 48 2. 79 Do. 5 5O 5O 17. 94 3. 23 D0. 6 60 40 20. 34 3. 67 D0. 7 70 30 17. 60 3.17 D0. 8 80 20 19.36 3. 48 Sli ht. 9 100 0 15.21 2. 74 Bad. I

All nine samples wer washed for 6 hours in a washing machine containing 25 parts of powdered soap in 13,000 parts of hot water at 70 C. They Example 5.A series of piperylene-butadiene copolymer emulsions was prepared. The two monomers were used in the proportions indicated in Table V.

. Table V Parts Parts 1 Emulsmn Number Piperylene Butadiene The butadiene was passed over CaCla and condensed in pressure reactors which were cooled to below -5 C. The exact amounts of butadiene were then weighed out in each pressure reactor and the piperylene was added, followed in each case by 50 parts of distilled water, 3 parts of a 10% solution of ammonium persulfate and 2.5 parts of soap (known to the trade as "Ivory Flakes), while the pressure reactors were still kept in the freezing mixture. The reactors were now closed and allowed to come to room temperature. They were then put in an agitator with a constant temperature bath at 45 C.

The reactors were taken out of the agitator at the end of 40 hours. They were cooled and opened. The reactors showed only very slight pressure on opening, thus indicating complete polymerization, which meant that the polymer content for each emulsion was 33V Example 6.-The four emulsions made according to Example 5 were applied to samples of wool flannel, 10" x 10" in size, on which four lengths of 8" each 'had been marked, two lengths in the direction ofthe warp, two lengths in the direction of the fill.

The samples weighed approximately 13 parts, An amount of emulsion containing a weight of polymer corresponding to 4.5% of the weight of the wool sample was added to 270 parts of water (20 times the weight of the wool). Approximately 3.5 parts of anhydrous sodium sulfate (26.5% based on the weight of the wool), were dissolved in 50 parts of water.

The wool samples were wetted in water at C. for 10 minutes and then immersed in the bath 10 at room temperature containing the emulsion. The bath was heated to 60 C. in the course of 15 minutes. Half of the sodium sulfate solution was now added followed 15 minutes later by the second half, while the bath was kept at 60 C. An

hour later the bath was still very cloudy and 2.0

parts of anhydrous sodium sulfate dissolved in 20 parts of water were added. Very little change took place and 15minutes later 3.0 parts of anhydrous sodium sulfate dissolved in 30 parts of water were added to the bath,'which was still kept at 60 C. After 15 minutes the wool samples were taken out, since no further change seemed to take place. A slight cloudiness .or haze was still left in the four baths, the cloudiness decreasing from the bath with emulsion #1 to the bath with emulsion #4. A total of approximately 8.5 parts of anhydrous sodium sulfate had been added to each bath and the exhaustion time, counted from Table VI sPherl (Lent Parts Parts r age Sample Piperylene Butadiene Felting Warp Fill 2. 5 22, 5 l9. 8 i. 0 Bad. 5. 0 2D. 0 21. 2 3. 8 D0. 7. 5 17. 5 23. 0 4.1 D0. 10. O 15. 0 20. 9 4. U DO. Untreated Sample 28. 0 12.0 Do.

Table VI shows the extent of the shrinkage and felting caused by the washing. It is evident that the shrinkproofing properties of piperylene-butadiene emulsions are inferior to those of isoprene-butadiene emulsions or dimethyl butadiene-butadiene emulsions. While the two last named emulsions exhibit very good results in shrinkprooflng, the piperylene-butadiene emulsions show only a very slight effect. This can probably be explained by the structure of -the monomers. Isoprene and dimethyl but"diene have the methyl groups on the beta-carbon, while I piperylene has the methyl group on the alphacarbon, which seems to be less favorable with regard to shrinkproofing characteristics.

Having thus set forth my invention, I claim:

1. A bath for treating wool to give shrinkproofing with substantially normal hand which comprises an aqueous substantially stable emulsion containing a synthetic copolymer of -100% polymerization, of butadiene 1.3 and from 10 to by weight in the copolymer of a 2, methyl butadiene 1.3 selected from the group consisting of isoprene and 2,3 dimethyl butadiene 1.3, in amount to give 1 to 25% by weight of copolymer deposition on the wool, a non-cationic emulsifying agent, and at least 25% by weight on the copolymer of a water-soluble neutral salt of an alkali metal as conditioning electrolyte, the pH of the bath being below '7.

2. A bath as set forth in claim 1, in which the 2, methyl butadiene is isoprene.

3. A bath as set forth in claim 1. in which the 2,

methyl butadiene is 2,3 dimethyl butadiene 1.3.

4. The methodof shrinkprooflng wool which comprises immersing the wool in a heated bath as set forth in claim 1, in which the bath is heated to a temperature of from 40 C. to the boiling point of the bath.

5. A bath as set forth in claim 1, in which the emulsifying agent is anionic.

6. A bath as set forth in claim 1 including an antioxidant for the copolymer.

7. A hath as set forth in claim 1, in which the 2, methyl butadiene is isoprene, and the bath includes an antioxidant for the copolymer.

8. A bath as set forth in claim 1, in which the 2, methyl butadiene is 2,3 dimethyl butadiene 1.3

and the bath includes an antioxidant for the copolymer.

301m a. near.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain Dec. 21, 1931 

